When refrigerant leakage occurs, a controller in an air conditioner performs first shutoff control to open a liquid relay shutoff valve and close an indoor expansion valve and a gas relay shutoff valve on the basis of information from a refrigerant leakage detector.

The invention relates to a method for low-temperature cooling/liquefaction of a working fluid, in particular a working fluid including helium or consisting of pure helium by means of a refrigerator/liquefier that includes a working circuit provided with a compressor station and a cold box. The refrigerator/liquefier subjects the working gas within the working circuit to a cycle that includes, in series: compressing the working fluid within the compressor station, cooling and decompressing the working fluid in the cold box, and heating the working fluid with a view to the return thereof to the compressor station. The compressor station includes one or more compression levels, each one using one or more compressors mounted on landings. The method is characterized in that the refrigerator includes a device for injecting a seal gas that is separate from the working fluid on at least one landing of the compressor(s) so as to form a gas seal that guides the working fluid leaks, coming from the working circuit, to an area for recirculating and returning the fluid into the working circuit.

A heat pump apparatus includes a refrigerant circuit for circulating combustible refrigerant, and a load unit to be provided in a room and configured to accommodate a load side heat exchanger. The load side heat exchanger allows heat exchange between the combustible refrigerant and a liquid heat medium. The load unit includes a fan, an air inlet for sucking in air from the room, and an air outlet for blowing out the air, sucked in from the air inlet, to the room. The air outlet is provided at a position of a height different from the height of the air inlet.

A fluid injection device (10) for injecting a dispensible fluid such as a liquid sealant (24) into an air conditioning or refrigeration system or the like, includes a tube (12, 12, 12) containing the fluid sealant in a storage chamber (26, 26, 26). Outlet valves conventionally used at the tube outlet are replaced with a rupturable membrane (28, 28, 66). Means to rupture the membrane may comprise a puncture tool (32, 50), or the membrane may be designed to burst under pressure imposed on it in use. Use of membrane (28, 28, 66) at the outlet of device 10 avoids problems caused by even very slight leakage of fluid sealant past an outlet valve. The fluid injection device (10) is used by connecting the tube inlet to a high pressure zone of the system and connecting the tube outlet to a low pressure zone of the system.

In one embodiment, an HVAC system includes an indoor unit having an indoor blower, an outdoor unit having a compressor and a condenser, an isolation valve coupled to the outdoor unit, and a sensor to detect a refrigerant leak. The HVAC system further includes one or more controllers operable to generate an alarm in response to the sensor detecting the refrigerant leak, operate the indoor blower in response to generating the alarm, close the isolation valve in response to generating the alarm, and operate the compressor to pump down the refrigerant to the condenser in response to generating the alarm.

When refrigerant leakage occurs, a controller in an air conditioner performs first shutoff control to open a liquid relay shutoff valve and close an indoor expansion valve and a gas relay shutoff valve on the basis of information from a refrigerant leakage detector.

A method including: determining whether a cooling system is operating in a cooling mode, such that the cooling system is not operating in a reheat mode, a humidification mode or a dehumidification mode; determining whether the cooling system is operating in a compressor mode, such that the cooling system is not operating in a pump refrigerant economization mode; determining whether the cooling system is at steady-state; and if the cooling system is operating in the cooling mode and the compressor mode and is at steady-state, evaluating one or more rules to determine if a degradation symptom exists for the cooling system. The method further includes: subsequent to the evaluation, generating a degradation evaluation value to indicate whether the one or more rules are satisfied; and based on the degradation evaluation value, generating an alarm signal or performing a countermeasure.

Device and method for injecting one or more additives into systems, such as a sealing agent to repair leaks in such systems, including air conditioning and refrigeration systems. In certain embodiments, the device is a disposable or single-use device, and includes a hose, tube, or conduit or the like that contains a sealing agent. Introduction of the sealing agent into the closed system allows the sealing agent to travel through the system and seal leaks therein. In some embodiments, one end of the hose is configured to connect to a manifold, and the other end of the device is configured to connect to the unit to be sealed. A check valve prevents unwanted backflow of refrigerant from the unit to be sealed.

When refrigerant leakage occurs, a controller in an air conditioner performs first shutoff control to open a liquid relay shutoff valve and close an indoor expansion valve and a gas relay shutoff valve on the basis of information from a refrigerant leakage detector.

A refrigeration cycle apparatus includes a refrigeration cycle circuit, a liquid receiver, a first valve and a second valve. The refrigeration cycle circuit includes a compressor, an outdoor heat exchanger and an indoor heat exchanger. The liquid receiver is provided in a second section located in the refrigeration cycle circuit. The second section is a section extending between the outdoor heat exchanger and the indoor heat exchanger without extending through the compressor. The first valve is provided in a first section in the refrigeration cycle circuit, and is a solenoid valve or a motor valve. The first section is a section extending between the outdoor heat exchanger and the indoor heat exchanger through the compressor. The second valve is provided in the second section and between the liquid receiver and the indoor heat exchanger, and is an electronic expansion valve, a solenoid valve or a motor valve.